Fertilization of a mixed forage crop with fresh and composted chicken manure and NPK fertilizer: Effects on soil and tissue Ca, Mg, S, B, Cu, Fe, Mn and Zn

A 3-yr experiment compared the effects of the fertilization of mixed forages with fresh and composted chicken manure and NPK fertilizer. Amendments were applied at three N levels, and an unfertilized treatment was included. The experiment was conducted in two hay fields: a sandy loam and a silty clay loam, near Truro, Nova Scotia. Mehlich 3- extractable Ca, Mg, S and micronutrients were reported for two depths of soil sampled in September 1993. In most cases, the Ca, Mg, S and micronutrient levels in the chicken manure compost and fresh manure were higher than the literature values. The Cu and Zn in both the fresh chicken manure and the compost exceeded the maximum concentrations for Category A (unrestricted use) compost. Compost treatments resulted in higher Ca in the upper horizon at both sites, but few differences among treatments were noted for soil Mg or S. Extractable soil Cu was not higher in the compost and manure plots in spite of the relatively high levels of Cu in the amendments. Compost-treated plots were numerically highest in soil Zn at the silty clay site, while the NPK plots had the highest Mehlich 3-extractable Fe at the same site. Fewer differences in soil levels of micronutrients were detected among treatments at the sandy loam site. Forage tissue Ca, Mg, S and micronutrients were reported for the 1993 season. The high rates of applications, especially for compost treatments, did not always result in higher nutrient levels in the forages; other factors that may have affected nutrient availability are suggested. It is concluded that higher rates of compost and manure could have been used in this experiment without risks of phyto- or ruminant toxicity.